International Cooperation (Mexico and Canada)
In response to the lack of freshwater resources in the U.S., two paths of action are possible: reducing U.S. water consumption or increasing the supply of water. A possibility that could increase water supply is to import the water from Canada, which has abundant quantities of freshwater and relatively low population density. In fact, although Canada encompasses 20% of the earth's total freshwater, it only has about 7% of its renewable supply. The other 13% is tied up in sources like fossil water, ice, and glaciers that Canada can only use once before the water re-enters the global water cycle.(Indian and Northern Affairs Canada, p.3)
The International Joint Commission, which seeks to mediate between Canada and the U.S. in issues related to shared watersheds, studied the possible effects of bulk water withdrawal in the Great Lakes. The agency concluded, in Protection of the Waters of the Great Lakes, that the joined effects of variables such as climate change, population growth, water consumption and impact of withdrawals, make it crucial to protect the ecology of the Great Lakes Basin. The environmental effects of bulk water removal from the basins are a primary concern as this could lead to invasion of alien microorganisms and species, spread of pollutants, shifts in water flow and overall changes in the local ecosystems.
The International Boundary Waters Treaty Act, created in 1911, was amended in 2002 to prohibit bulk removal of Canadian boundary water. Although the amendment was actually aimed at the Great Lakes, all Canadian provinces have embraced similar policies.
A current concern is that the North American Trade Agreement (NAFTA) which removes most barriers to trade and investment among the United States, Canada, and Mexico, only includes bottled water, and not bulk water as a tradable good, although it does not explicitly prohibit its commerce. (Canada International, 1999)
The arid region surrounding the 3141 km border between the United States and Mexico is inhabited by about 10.5 million people. Two major rivers, the Rio Grande and the Colorado, run through this area from the United States to Mexico before discharging into the Gulfs of Mexico and California, respectively. Water from these two rivers and their tributaries, in addition to available groundwater, supply the water for traditional irrigated agriculture, industry, and municipal purposes.
The International Boundary and Water Commission (IBWC) is dedicated to resolving issues concerning water use along the US-Mexico border and allocations of international water sources, according to the 1944 Water Treaty between the United States and Mexico. The IBWC has been confronted with controversies concerning contaminates such as salt and sediment and the delivery of water, especially in times of drought or flood. High levels of saline runoff and silt from irrigation have greatly reduced the quality of the water that Mexico receives from the United States and drought in recent years has caused Mexico to fail to uphold its quota of water to be returned to the United States, resulting in a water debt that was paid off in September 2005. However, the years of water deficiency crippled agriculture in Texas.
The 1944 Water treaty between Mexico and the United States of America (USA) guarantees Mexico 1.5 million acre-feet of water from the Colorado River, and the USA one third of the water flowing from the Rio Grande, which benefits 28 irrigation districts in Texas. In case of extraordinary drought, the treaty includes a clause that enables Mexico to deliver less than a minimum amount of water in a five-year cycle, but requires making up the deficit over the next five years.
In the 1990s, because of a drought along the Rio Grande and the rapid development in the lower basin, Mexico acquired a water debt that greatly affected Texan farmers who require water from the Rio Grande for irrigation. By 1997, Mexico's water deficit was 1,023,849 acre-feet. As of 2002 Mexico owed about 1.5 million acre-feet of water to the United States in accordance with the 1944 treaty. Mexico had to deliver an average of at least 350,000 acre-feet of water per year to the United States in five year cycles, starting on 1997 (Fischhendler, Feitelson, Eaton, 2004). This water debt caused annual losses estimated at about US $978 million to the 28 Texas irrigation districts that depend on this water transfer. Also, the Rio Grande Regional Water Planning Group, in a 2002 study (ten years into the water deficit), estimated that Texas would have "gained more than $100 million in gross regional product statewide" and over 3300 jobs if Mexico had paid the minimum debt that year (2002, The Rio Grande Regional Water Planning Group).
This issue led to many meetings, debates and measures, including Minute 234 which guaranteed the delivery of 300,000 acre-feet of water from the two international reservoirs, Minute 308, signed in 2002, in which the North American Trade Bank agreed to aid money to improve Mexico's irrigation system along the Rio Grande, and Minute 309 which agrees that one third of the water saved as consequence of the improved irrigation system will pay part of the water debt (Fischhendler, Feitelson, Eaton, 2004, pp. 643-644).
Mexico repaid its accumulated water debt in 2005 and has accrued none since then. In March 2005, with the announcement that Mexico would pay its debt, the United States and Mexico announced a joint intent not only to formalize procedures for operations under drought, but to "meet annually to review basin conditions, develop firm water delivery plans for the next cycle year, and work cooperatively on drought management strategies that can benefit both countries" (Environment News, 2008).
The Colorado River runs along 38km of the border between the United States and Mexico. The 1944 Water Treaty allots Mexico 1.5 million acre-feet of water from the Colorado River each year. One-hundred and eighty kilometers north of the border, at the Parker Dam, water is diverted via aqueducts to various states and counties. These aqueducts provide water to the states of Arizona and California, and reach cities such as Los Angeles, San Diego, Tucson, and Phoenix. This water reaches a total population of 14 million. Further below the Parker Dam is the Imperial Dam, which provides water to California and Arizona to irrigate 277,854 hectares of farmland. In addition to domestic use, this river provides water for vegetation in native riparian areas and is an important part of the north-south migratory bird flyway. Mexico diverts water just south of the border which is used to irrigate 124,000 hectares of agriculture in the Mexicali and San Luis Valleys. An aqueduct also transports water to several cities, providing for a population of about 2 million. These cities include Mexicali, Tecate, Tijuana, and Ensenada (2000, Solis Bernal).
During the first years of the Treaty, Mexico received good quality water of less than 900 ppm TDS (parts per million total dissolved solids) ; however in the 1960's and early 1970's high salinity levels, up to 14,500 ppm, were recorded in the Colorado River Delta (Marin, 2008). In a 1974 study, it was found that the sources of the high salinity concentrations in the water were both natural and anthropogenic. While about 47 percent of the salinity was attributed to natural causes, about 37 percent was due to irrigation , 12 percent to reservoir evaporation and uptake by phreatophytes , 3 percent, were out-of-basin exports, and 1 percent was attributed to municipal and industrial uses. Much of this contribution from irrigated agriculture is from federally-developed irrigation projects. (Colorado River Basin Salinity Control Forum, 2008 p.2).
After years of negotiation, on August 30, 1973, both governments signed an agreement, the Permanent and Definitive Solution to the International Problem of the Salinity of the Colorado River, incorporated into Minute No. 242 of the 1944 Water Treaty, which established that the waters received by Mexico in the Morelos Dam (the dam that first stores water from the Colorado River along the Mexican segment of the river) must have an annual average salinity of no more than 115 ppm +- 30ppm over the annual average salinity of the waters that arrive at the Imperial Dam (the dam that stores the Colorado River waters upstream from the Morelos Dam on the American side of the river) (Marin,2008 p.2). Also, the maximum salinity levels that must be met at the Imperial Dam is of 879 mg/L (Colorado River Basin Salinity Control Forum, 2008 p. iv).
As consequence of this agreement, the Yuma desalting plant was built in order to decrease salinity of the pumped discharge water from the Wellton- Mohawk irrigation and Discharge District before it returned to the Colorado River. The Yuma desalting plant, which recovers at least seventy percent of the drain water by using reverse-osmosis technology and is the biggest in the U.S.A., stopped operations in 1993, when the quality of water received by the Northern International Boundary at Mexico had improved. Another measure taken to reduce salinity, before the desalting plant project was completed, was discharging all Wellton-Mohawk pumped drainage water into the United States Bypass Drain, which would convey these waters to the Santa Clara Slough on the Gulf of California in Mexico, and then would substitute it with better quality water from upstream storage. Also, by recommendation of the International Task Force, during four months of each year, up to 8000 acre-feet of drainage water from the Boundary Pumping Plant would be diverted to the U.S. Bypass Drain and would be replaced with better quality water from the Minute 242 Well Field. Currently, there are limits to the amounts of groundwater that can be pumped to the Arizona-Sonora boundary near San Luis. Minute 242 limits pumping of groundwater in its territory within five miles of the Arizona-Sonora boundary to 160000 acre-feet annually. In 2006 Mexico pumped 141,693 acre-feet, while the U.S. pumped 47,975 acre-feet. The Bureau of Reclamation has built 21 wells and has deferred 14 planned wells until additional water supply needs make it necessary.
Other recommendations of the International Task Force included structural modifications to the water delivery system at the Southern International Boundary and the installation of speed motor controllers, a method to reduce the salinity and variability of flow delivered to Mexico. These controllers allow a pump to gradually increase the rate of discharge, thus guaranteeing that the volume of water leaving being diverted is the same volume being received. They also recommended the construction of a bifurcation structure with three sluice gates, a construction of a 7000-foot concrete-lined diversion channel from the Boundary Pumping Plant to the U.S. Bypass Drain and a control panel for the operation of all pumps and sluice gates. All of the facilities have been completed except a remotely operated salinity monitoring and control system, due to equipment problems (Marin, 2008 pp 4-7).
According to the Colorado River Salinity Control Forum's 2008 Review, if additional water development projects occur, besides the ones expected, increases of salinity concentration above the ones set by the Minute 242 may take place. Throughout the years, there have been shifts in crops grown on the irrigated land of the Lower Basin. While in the mid 70s low value, salt tolerant plants were grown, with the passage of time, there has been a shift to higher value, less salt tolerant crops. These types of crops are particularly susceptible to elevated levels of boron and sodium. This agricultural shift has resulted in economic losses due to high salinity concentrations on the water used for irrigation. The concentrations of salts have been increasing over the last few years, and the recent and significant drought could be a cause of these increases. Salinity may also increase due to natural variations of the hydrologic cycle cuased largely by drought. When the river flows are below the long-term means, salinity concentrations may vary up to 250 mg/L (Colorado River Basin Salinity Control Forum, 2008 pp.7-8).
The water received by Mexico from the Colorado River is used for both irrigation and domestic uses. Currently, the waters serve to irrigate about 124,000 acres in the area of the Mexcali Valley of Sonora and Valle San Luis. High salinity levels, which in great part are due to irrigation run-off, directly affect the subsequently irrigated Mexican land and the domestic water users. Although the salinity levels that enter the Morelos Dam have significantly decreased, there are temporary high salinity peaks and they are expected to increase in the future. Since the set salinity standards are being met, it has not been operating for about 15 years, and the source for the quality water that is being received by Mexico is groundwater.
In order to fulfill the binational agreement with measures that benefit both countries by providing high quality water to Mexico from the Colorado River in perpetuity , we must eliminate dependence on groundwater, a non-renwable resource.